Page 51 - MNU PM502 Ph. Micreo practical

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

- The dilutions of the disinfectant are made in hard water for clean

conditions and in yeast suspension for dirty conditions.

- Test organism alone or with yeast is added at 0-, 10- and 20-minutes’

interval.

- The contact time of disinfectant and test organism is 8 min, 18 min, 28

min

Practical mission:

You are provided with a test tube containing a test disinfectant, and a bacterial

suspension of E. coli. Determine the capacity of the disinfectant using Kelsey-

Sykes test.

Equipments

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1. 10 ml standardized bacterial suspension (2x10 cfu/ ml)
2. A test disinfectant (3ml)
3. 3 empty sterile test tubes

4. Flask of sterile water

5. 15 sterile test tubes containing 10 ml n. broth for each concentration.
6. 1 ml sterile pipette

Steps:

1. In the empty tubes, prepare different concentrations/ dilutions of the test

disinfectants (1%, 1.5%, 2%)

2. For the first concertation tube

At zero time: By a 1 ml pipette, transfer 1ml of the bacterial suspension to the

disinfectant tube.

• Transfer 0.02 ml of the disinfectant/culture mixture to 9ml of sterile n.

broth in five replicates after 8 min.

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